A camshaft adjuster of this type is known from DE 10 2012 223 582 A1, for example, relating to a camshaft adjuster system which includes a camshaft adjuster and a camshaft, the camshaft adjuster including a drive element and an output element situated so that it is pivotable with respect to the drive element, the output element being connected to the camshaft in a rotatably fixed manner, a cover element being rotatably fixedly fastened to the output element and the hub of the cover element being situated between the drive element and the camshaft, the radial direction of extension of the cover element being greater than the diameter of the contact surface of the cover element with respect to the camshaft.
Gas exchange valves of internal combustion engines may be actuated by cams of a camshaft. The opening and closing times of the gas exchange valves are settable in a targeted manner via the configuration and shape of the cams. The camshaft is generally actuated, driven, and/or controlled by the crankshaft of the internal combustion engine. The opening and closing times of the gas exchange valves of the internal combustion engine are generally specified by a relative rotational position or phase position or angular position between the cams and the crankshaft. As the result of a relative change in this relative rotational position between the camshaft and the crankshaft, a variable adjustment of the opening and closing times of the gas exchange valves may be achieved. Due to the variable adjustment of the opening and closing times of the gas exchange valves, for example the exhaust gas characteristics may be positively influenced, the fuel consumption may be reduced, the efficiency may be increased, and/or the maximum torque and/or the maximum power of the internal combustion engine may be increased as a function of the instantaneous operating state of the internal combustion engine.
This variable adjustment of the opening and closing times of the gas exchange valves may be made, or made possible, by a provided camshaft adjustment device or unit or such a camshaft adjuster between the crankshaft and the camshaft.
For this purpose, a camshaft adjuster is generally provided in the kinematic chain between the crankshaft and the camshaft. A portion of the camshaft adjuster, referred to below as the stator, is rotatably fixedly connected to the crankshaft. Another portion of the camshaft adjuster, referred to below as the rotor, is rotatably fixedly connected to the camshaft. A gear is customarily provided between the stator and the rotor. For a hydraulic camshaft adjuster of the vane cell type, this gear is generally provided as a hydraulically actuated vane cell or as a plurality of such vane cells. The variable adjustment of the opening and closing times of the gas exchange valves may be achieved by the action of hydraulic pressure on the vane cells. This embodiment may also be referred to as a rotary piston adjuster. However, it is pointed out here that the present invention is not limited to camshaft adjusters of the vane cell type, and that in principle, other types of camshaft adjusters may also be used.
A camshaft adjuster is generally centered for installation on the particular camshaft via a cylindrical surface that extends in an axial direction of the camshaft. In DE 10 2012 223 582 A1, this is referred to, for example, as the hub of the cover element. Providing this cylindrical surface has disadvantages. It is thus necessary for this cylindrical surface to have a certain axial extension, also referred to as a centering depth, and therefore installation space in the camshaft adjuster is required. This installation space or this volume is therefore no longer available for other design measures, such as providing a borehole. A large amount of installation space is also necessary overall, which is undesirable on its own. Another disadvantage is that the camshaft adjuster is subject to being adjusted during installation; for example, an angular position or a phase position may be set, or a belt drive, a chain drive, or the like may be set or mounted on the adjuster, while the camshaft adjuster is not secured against slipping or coming off in the axial direction.